Imaging is at the forefront of modern smartphones. But with the main phone manufacturers fighting it out to claim they have the best camera on their handset, it's the third-party app developers that are really capturing the imagination.

Just look at the likes of Hipstamatic or the recently acquired Instagram. These apps have nothing to do with the technical capabilities (or failings) of a phone's camera, but are hugely popular by being distinct and adding character. There are plenty of other fun options out there too and today we're looking at one such creative camera app.

After Focus

After Focus, as the name suggests, offers you the chance to apply effects after you've taken a shot. The approach is interesting because it gives you the ability to mask parts of your photo, so you make changes only to particular elements.

This is the derivative of the "focus" part of the name, as the main suggestion is creating a wide aperture effect, blurring background to emphasise the subject.

It's easy to do too. You simply paint over the parts of the image, identifying whether you're working on the focused area or background, press the button and blur comes in.

There are manual or smart options - we found that we liked the direct control that manual offers - to help you get the results you want. There is also the option to zoom, so you can really get into the detail for the best results.

But that's not all. After Focus offers a great deal more. Once you're through the blurring phase (and you can mask the entire thing if you want no blur) you get access to a range of common effects.

You'll find you can change the strength of the blur effect, make it look like motion blur to give the illusion of movement, or add a vignette, sharpen the image or add a bokeh effect to background highlights.

You can also use your selected area as a colour mask, to strip all the colour out of the background for real emphasis, or apply more common cross process or antique effects to add that finishing touch.

There are plenty of photo apps out there, but we like some of the features that After Focus offers. Being able to mask the subject can allow for some dramatic results, so it's worth playing around with.